/*
 * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 *
 */

package java.sql;

import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;

/**
 * <P>An exception that provides information on a database access
 * error or other errors.
 *
 * <P>Each <code>SQLException</code> provides several kinds of information:
 * <UL>
 * <LI> a string describing the error.  This is used as the Java Exception
 * message, available via the method <code>getMesasge</code>.
 * <LI> a "SQLstate" string, which follows either the XOPEN SQLstate conventions
 * or the SQL:2003 conventions.
 * The values of the SQLState string are described in the appropriate spec.
 * The <code>DatabaseMetaData</code> method <code>getSQLStateType</code>
 * can be used to discover whether the driver returns the XOPEN type or
 * the SQL:2003 type.
 * <LI> an integer error code that is specific to each vendor.  Normally this will
 * be the actual error code returned by the underlying database.
 * <LI> a chain to a next Exception.  This can be used to provide additional
 * error information.
 * <LI> the causal relationship, if any for this <code>SQLException</code>.
 * </UL>
 */
public class SQLException extends java.lang.Exception
        implements Iterable<Throwable> {

    /**
     * Constructs a <code>SQLException</code> object with a given
     * <code>reason</code>, <code>SQLState</code>  and
     * <code>vendorCode</code>.
     * <p>
     * The <code>cause</code> is not initialized, and may subsequently be
     * initialized by a call to the
     * {@link Throwable#initCause(java.lang.Throwable)} method.
     * <p>
     *
     * @param reason     a description of the exception
     * @param SQLState   an XOPEN or SQL:2003 code identifying the exception
     * @param vendorCode a database vendor-specific exception code
     */
    public SQLException(String reason, String SQLState, int vendorCode) {
        super(reason);
        this.SQLState = SQLState;
        this.vendorCode = vendorCode;
        if (!(this instanceof SQLWarning)) {
            if (DriverManager.getLogWriter() != null) {
                DriverManager.println("SQLState(" + SQLState +
                        ") vendor code(" + vendorCode + ")");
                printStackTrace(DriverManager.getLogWriter());
            }
        }
    }


    /**
     * Constructs a <code>SQLException</code> object with a given
     * <code>reason</code> and <code>SQLState</code>.
     * <p>
     * The <code>cause</code> is not initialized, and may subsequently be
     * initialized by a call to the
     * {@link Throwable#initCause(java.lang.Throwable)} method. The vendor code
     * is initialized to 0.
     * <p>
     *
     * @param reason   a description of the exception
     * @param SQLState an XOPEN or SQL:2003 code identifying the exception
     */
    public SQLException(String reason, String SQLState) {
        super(reason);
        this.SQLState = SQLState;
        this.vendorCode = 0;
        if (!(this instanceof SQLWarning)) {
            if (DriverManager.getLogWriter() != null) {
                printStackTrace(DriverManager.getLogWriter());
                DriverManager.println("SQLException: SQLState(" + SQLState + ")");
            }
        }
    }

    /**
     * Constructs a <code>SQLException</code> object with a given
     * <code>reason</code>. The  <code>SQLState</code>  is initialized to
     * <code>null</code> and the vendor code is initialized to 0.
     * <p>
     * The <code>cause</code> is not initialized, and may subsequently be
     * initialized by a call to the
     * {@link Throwable#initCause(java.lang.Throwable)} method.
     * <p>
     *
     * @param reason a description of the exception
     */
    public SQLException(String reason) {
        super(reason);
        this.SQLState = null;
        this.vendorCode = 0;
        if (!(this instanceof SQLWarning)) {
            if (DriverManager.getLogWriter() != null) {
                printStackTrace(DriverManager.getLogWriter());
            }
        }
    }

    /**
     * Constructs a <code>SQLException</code> object.
     * The <code>reason</code>, <code>SQLState</code> are initialized
     * to <code>null</code> and the vendor code is initialized to 0.
     * <p>
     * The <code>cause</code> is not initialized, and may subsequently be
     * initialized by a call to the
     * {@link Throwable#initCause(java.lang.Throwable)} method.
     */
    public SQLException() {
        super();
        this.SQLState = null;
        this.vendorCode = 0;
        if (!(this instanceof SQLWarning)) {
            if (DriverManager.getLogWriter() != null) {
                printStackTrace(DriverManager.getLogWriter());
            }
        }
    }

    /**
     * Constructs a <code>SQLException</code> object with a given
     * <code>cause</code>.
     * The <code>SQLState</code> is initialized
     * to <code>null</code> and the vendor code is initialized to 0.
     * The <code>reason</code>  is initialized to <code>null</code> if
     * <code>cause==null</code> or to <code>cause.toString()</code> if
     * <code>cause!=null</code>.
     * <p>
     *
     * @param cause the underlying reason for this <code>SQLException</code>
     *              (which is saved for later retrieval by the <code>getCause()</code> method);
     *              may be null indicating the cause is non-existent or unknown.
     * @since 1.6
     */
    public SQLException(Throwable cause) {
        super(cause);

        if (!(this instanceof SQLWarning)) {
            if (DriverManager.getLogWriter() != null) {
                printStackTrace(DriverManager.getLogWriter());
            }
        }
    }

    /**
     * Constructs a <code>SQLException</code> object with a given
     * <code>reason</code> and  <code>cause</code>.
     * The <code>SQLState</code> is  initialized to <code>null</code>
     * and the vendor code is initialized to 0.
     * <p>
     *
     * @param reason a description of the exception.
     * @param cause  the underlying reason for this <code>SQLException</code>
     *               (which is saved for later retrieval by the <code>getCause()</code> method);
     *               may be null indicating the cause is non-existent or unknown.
     * @since 1.6
     */
    public SQLException(String reason, Throwable cause) {
        super(reason, cause);

        if (!(this instanceof SQLWarning)) {
            if (DriverManager.getLogWriter() != null) {
                printStackTrace(DriverManager.getLogWriter());
            }
        }
    }

    /**
     * Constructs a <code>SQLException</code> object with a given
     * <code>reason</code>, <code>SQLState</code> and  <code>cause</code>.
     * The vendor code is initialized to 0.
     * <p>
     *
     * @param reason   a description of the exception.
     * @param sqlState an XOPEN or SQL:2003 code identifying the exception
     * @param cause    the underlying reason for this <code>SQLException</code>
     *                 (which is saved for later retrieval by the
     *                 <code>getCause()</code> method); may be null indicating
     *                 the cause is non-existent or unknown.
     * @since 1.6
     */
    public SQLException(String reason, String sqlState, Throwable cause) {
        super(reason, cause);

        this.SQLState = sqlState;
        this.vendorCode = 0;
        if (!(this instanceof SQLWarning)) {
            if (DriverManager.getLogWriter() != null) {
                printStackTrace(DriverManager.getLogWriter());
                DriverManager.println("SQLState(" + SQLState + ")");
            }
        }
    }

    /**
     * Constructs a <code>SQLException</code> object with a given
     * <code>reason</code>, <code>SQLState</code>, <code>vendorCode</code>
     * and  <code>cause</code>.
     * <p>
     *
     * @param reason     a description of the exception
     * @param sqlState   an XOPEN or SQL:2003 code identifying the exception
     * @param vendorCode a database vendor-specific exception code
     * @param cause      the underlying reason for this <code>SQLException</code>
     *                   (which is saved for later retrieval by the <code>getCause()</code> method);
     *                   may be null indicating the cause is non-existent or unknown.
     * @since 1.6
     */
    public SQLException(String reason, String sqlState, int vendorCode, Throwable cause) {
        super(reason, cause);

        this.SQLState = sqlState;
        this.vendorCode = vendorCode;
        if (!(this instanceof SQLWarning)) {
            if (DriverManager.getLogWriter() != null) {
                DriverManager.println("SQLState(" + SQLState +
                        ") vendor code(" + vendorCode + ")");
                printStackTrace(DriverManager.getLogWriter());
            }
        }
    }

    /**
     * Retrieves the SQLState for this <code>SQLException</code> object.
     *
     * @return the SQLState value
     */
    public String getSQLState() {
        return (SQLState);
    }

    /**
     * Retrieves the vendor-specific exception code
     * for this <code>SQLException</code> object.
     *
     * @return the vendor's error code
     */
    public int getErrorCode() {
        return (vendorCode);
    }

    /**
     * Retrieves the exception chained to this
     * <code>SQLException</code> object by setNextException(SQLException ex).
     *
     * @return the next <code>SQLException</code> object in the chain;
     * <code>null</code> if there are none
     * @see #setNextException
     */
    public SQLException getNextException() {
        return (next);
    }

    /**
     * Adds an <code>SQLException</code> object to the end of the chain.
     *
     * @param ex the new exception that will be added to the end of
     *           the <code>SQLException</code> chain
     * @see #getNextException
     */
    public void setNextException(SQLException ex) {

        SQLException current = this;
        for (; ; ) {
            SQLException next = current.next;
            if (next != null) {
                current = next;
                continue;
            }

            if (nextUpdater.compareAndSet(current, null, ex)) {
                return;
            }
            current = current.next;
        }
    }

    /**
     * Returns an iterator over the chained SQLExceptions.  The iterator will
     * be used to iterate over each SQLException and its underlying cause
     * (if any).
     *
     * @return an iterator over the chained SQLExceptions and causes in the proper
     * order
     * @since 1.6
     */
    public Iterator<Throwable> iterator() {

        return new Iterator<Throwable>() {

            SQLException firstException = SQLException.this;
            SQLException nextException = firstException.getNextException();
            Throwable cause = firstException.getCause();

            public boolean hasNext() {
                if (firstException != null || nextException != null || cause != null)
                    return true;
                return false;
            }

            public Throwable next() {
                Throwable throwable = null;
                if (firstException != null) {
                    throwable = firstException;
                    firstException = null;
                } else if (cause != null) {
                    throwable = cause;
                    cause = cause.getCause();
                } else if (nextException != null) {
                    throwable = nextException;
                    cause = nextException.getCause();
                    nextException = nextException.getNextException();
                } else
                    throw new NoSuchElementException();
                return throwable;
            }

            public void remove() {
                throw new UnsupportedOperationException();
            }

        };

    }

    /**
     * @serial
     */
    private String SQLState;

    /**
     * @serial
     */
    private int vendorCode;

    /**
     * @serial
     */
    private volatile SQLException next;

    private static final AtomicReferenceFieldUpdater<SQLException, SQLException> nextUpdater =
            AtomicReferenceFieldUpdater.newUpdater(SQLException.class, SQLException.class, "next");

    private static final long serialVersionUID = 2135244094396331484L;
}
